#ifndef ___DLIST_H
#define ___DLIST_H

#include <stddef.h>

/**
 * container_of - cast a member of a structure out to the containing structure
 * @ptr:	the pointer to the member.
 * @type:	the type of the container struct this is embedded in.
 * @member:	the name of the member within the struct.
 *
 */
/*#define container_of(ptr, type, member) ({				\
  const typeof( ((type *)0)->member ) *__mptr = (ptr);	\
  (type *)( (char *)__mptr - offsetof(type,member) );})
*/
#define container_of(ptr, type, member)					\
     ((type *)((char *)(ptr)-(unsigned long)(&((type *)0)->member)))
/*
 * Simple doubly linked list implementation.
 *
 * Some of the internal functions ("__xxx") are useful when
 * manipulating whole lists rather than single entries, as
 * sometimes we already know the next/prev entries and we can
 * generate better code by using them directly rather than
 * using the generic single-entry routines.
 */

typedef struct list_head list_head_t;

struct list_head {
     struct list_head *next, *prev;
};

#define LIST_HEAD_INIT(name) { &(name), &(name) }

#define LIST_HEAD(name)					\
     struct list_head name = LIST_HEAD_INIT(name)

static inline void INIT_LIST_HEAD(struct list_head *list)
{
     list->next = list;
     list->prev = list;
}

/*
 * Insert a new entry between two known consecutive entries.
 *
 * This is only for internal list manipulation where we know
 * the prev/next entries already!
 */
static inline void __list_add(struct list_head *new,
			      struct list_head *prev,
			      struct list_head *next)
{
     next->prev = new;
     new->next = next;
     new->prev = prev;
     prev->next = new;
}

/**
 * list_add - add a new entry
 * @new: new entry to be added
 * @head: list head to add it after
 *
 * Insert a new entry after the specified head.
 * This is good for implementing stacks.
 */
static inline void list_add(struct list_head *new, struct list_head *head)
{
     __list_add(new, head, head->next);
}


/**
 * list_add_tail - add a new entry
 * @new: new entry to be added
 * @head: list head to add it before
 *
 * Insert a new entry before the specified head.
 * This is useful for implementing queues.
 */
static inline void list_add_tail(struct list_head *new, struct list_head *head)
{
     __list_add(new, head->prev, head);
}

/*
 * Delete a list entry by making the prev/next entries
 * point to each other.
 *
 * This is only for internal list manipulation where we know
 * the prev/next entries already!
 */
static inline void __list_del(struct list_head * prev, struct list_head * next)
{
     next->prev = prev;
     prev->next = next;
}

/**
 * list_del - deletes entry from list.
 * @entry: the element to delete from the list.
 * Note: list_empty() on entry does not return true after this, the entry is
 * in an undefined state.
 */

static inline void list_del(struct list_head *entry)
{
     __list_del(entry->prev, entry->next);
     entry->next = (void *) 0;
     entry->prev = (void *) 0;
}

/**
 * list_replace - replace old entry by new one
 * @old : the element to be replaced
 * @new : the new element to insert
 *
 * If @old was empty, it will be overwritten.
 */
static inline void list_replace(struct list_head *old,
				struct list_head *new)
{
     new->next = old->next;
     new->next->prev = new;
     new->prev = old->prev;
     new->prev->next = new;
}

static inline void list_replace_init(struct list_head *old,
				     struct list_head *new)
{
     list_replace(old, new);
     INIT_LIST_HEAD(old);
}

/**
 * list_del_init - deletes entry from list and reinitialize it.
 * @entry: the element to delete from the list.
 */
static inline void list_del_init(struct list_head *entry)
{
     __list_del(entry->prev, entry->next);
     INIT_LIST_HEAD(entry);
}

/**
 * list_move - delete from one list and add as another's head
 * @list: the entry to move
 * @head: the head that will precede our entry
 */
static inline void list_move(struct list_head *list, struct list_head *head)
{
     __list_del(list->prev, list->next);
     list_add(list, head);
}

/**
 * list_move_tail - delete from one list and add as another's tail
 * @list: the entry to move
 * @head: the head that will follow our entry
 */
static inline void list_move_tail(struct list_head *list,
				  struct list_head *head)
{
     __list_del(list->prev, list->next);
     list_add_tail(list, head);
}

/**
 * list_is_last - tests whether @list is the last entry in list @head
 * @list: the entry to test
 * @head: the head of the list
 */
static inline int list_is_last(const struct list_head *list,
			       const struct list_head *head)
{
     return list->next == head;
}

/**
 * list_empty - tests whether a list is empty
 * @head: the list to test.
 */
static inline int list_empty(const struct list_head *head)
{
     return head->next == head;
}

/**
 * list_empty_careful - tests whether a list is empty and not being modified
 * @head: the list to test
 *
 * Description:
 * tests whether a list is empty _and_ checks that no other CPU might be
 * in the process of modifying either member (next or prev)
 *
 * NOTE: using list_empty_careful() without synchronization
 * can only be safe if the only activity that can happen
 * to the list entry is list_del_init(). Eg. it cannot be used
 * if another CPU could re-list_add() it.
 */
static inline int list_empty_careful(const struct list_head *head)
{
     struct list_head *next = head->next;
     return (next == head) && (next == head->prev);
}

/**
 * list_is_singular - tests whether a list has just one entry.
 * @head: the list to test.
 */
static inline int list_is_singular(const struct list_head *head)
{
     return !list_empty(head) && (head->next == head->prev);
}

static inline void __list_cut_position(struct list_head *list,
				       struct list_head *head, struct list_head *entry)
{
     struct list_head *new_first = entry->next;
     list->next = head->next;
     list->next->prev = list;
     list->prev = entry;
     entry->next = list;
     head->next = new_first;
     new_first->prev = head;
}

/**
 * list_cut_position - cut a list into two
 * @list: a new list to add all removed entries
 * @head: a list with entries
 * @entry: an entry within head, could be the head itself
 *	and if so we won't cut the list
 *
 * This helper moves the initial part of @head, up to and
 * including @entry, from @head to @list. You should
 * pass on @entry an element you know is on @head. @list
 * should be an empty list or a list you do not care about
 * losing its data.
 *
 */
static inline void list_cut_position(struct list_head *list,
				     struct list_head *head, struct list_head *entry)
{
     if (list_empty(head))
	  return;
     if (list_is_singular(head) &&
	 (head->next != entry && head != entry))
	  return;
     if (entry == head)
	  INIT_LIST_HEAD(list);
     else
	  __list_cut_position(list, head, entry);
}

static inline void __list_splice(const struct list_head *list,
				 struct list_head *prev,
				 struct list_head *next)
{
     struct list_head *first = list->next;
     struct list_head *last = list->prev;

     first->prev = prev;
     prev->next = first;

     last->next = next;
     next->prev = last;
}

/**
 * list_splice - join two lists, this is designed for stacks
 * @list: the new list to add.
 * @head: the place to add it in the first list.
 */
static inline void list_splice(const struct list_head *list,
			       struct list_head *head)
{
     if (!list_empty(list))
	  __list_splice(list, head, head->next);
}

/**
 * list_splice_tail - join two lists, each list being a queue
 * @list: the new list to add.
 * @head: the place to add it in the first list.
 */
static inline void list_splice_tail(struct list_head *list,
				    struct list_head *head)
{
     if (!list_empty(list))
	  __list_splice(list, head->prev, head);
}

/**
 * list_splice_init - join two lists and reinitialise the emptied list.
 * @list: the new list to add.
 * @head: the place to add it in the first list.
 *
 * The list at @list is reinitialised
 */
static inline void list_splice_init(struct list_head *list,
				    struct list_head *head)
{
     if (!list_empty(list)) {
	  __list_splice(list, head, head->next);
	  INIT_LIST_HEAD(list);
     }
}

/**
 * list_splice_tail_init - join two lists and reinitialise the emptied list
 * @list: the new list to add.
 * @head: the place to add it in the first list.
 *
 * Each of the lists is a queue.
 * The list at @list is reinitialised
 */
static inline void list_splice_tail_init(struct list_head *list,
					 struct list_head *head)
{
     if (!list_empty(list)) {
	  __list_splice(list, head->prev, head);
	  INIT_LIST_HEAD(list);
     }
}

/**
 * list_entry - get the struct for this entry
 * @ptr:	the &struct list_head pointer.
 * @type:	the type of the struct this is embedded in.
 * @member:	the name of the list_struct within the struct.
 */
#define list_entry(ptr, type, member)		\
     container_of(ptr, type, member)

/**
 * list_first_entry - get the first element from a list
 * @ptr:	the list head to take the element from.
 * @type:	the type of the struct this is embedded in.
 * @member:	the name of the list_struct within the struct.
 *
 * Note, that list is expected to be not empty.
 */
#define list_first_entry(ptr, type, member)	\
     list_entry((ptr)->next, type, member)

/**
******************************
* list_last_entry - get the last element from a list
* @ptr:	the list head to take the element from.
* @type:	the type of the struct this is embedded in.
* @member:	the name of the list_struct within the struct.
*
* Note, that list is expected to be not empty.
*/
#define list_last_entry(ptr, type, member)	\
     list_entry((ptr)->prev, type, member)

/**
 * list_for_each	-	iterate over a list
 * @pos:	the &struct list_head to use as a loop cursor.
 * @head:	the head for your list.
 */
#define list_for_each(pos, head)		\
     for (pos = (head)->next; pos != (head);	\
	  pos = pos->next)

/**
 * __list_for_each	-	iterate over a list
 * @pos:	the &struct list_head to use as a loop cursor.
 * @head:	the head for your list.
 *
 * This variant differs from list_for_each() in that it's the
 * simplest possible list iteration code, no prefetching is done.
 * Use this for code that knows the list to be very short (empty
 * or 1 entry) most of the time.
 */
#define __list_for_each(pos, head)				\
     for (pos = (head)->next; pos != (head); pos = pos->next)

/**
 * list_for_each_prev	-	iterate over a list backwards
 * @pos:	the &struct list_head to use as a loop cursor.
 * @head:	the head for your list.
 */
#define list_for_each_prev(pos, head)		\
     for (pos = (head)->prev; pos != (head);	\
	  pos = pos->prev)

/**
 * list_for_each_safe - iterate over a list safe against removal of list entry
 * @pos:	the &struct list_head to use as a loop cursor.
 * @n:		another &struct list_head to use as temporary storage
 * @head:	the head for your list.
 */
#define list_for_each_safe(pos, n, head)			\
     for (pos = (head)->next, n = pos->next; pos != (head);	\
	  pos = n, n = pos->next)

/**
 * list_for_each_prev_safe - iterate over a list backwards safe against removal of list entry
 * @pos:	the &struct list_head to use as a loop cursor.
 * @n:		another &struct list_head to use as temporary storage
 * @head:	the head for your list.
 */
#define list_for_each_prev_safe(pos, n, head)	\
     for (pos = (head)->prev, n = pos->prev;	\
	  pos != (head);			\
	  pos = n, n = pos->prev)

/**
 * list_for_each_entry	-	iterate over list of given type
 * @pos:	the type * to use as a loop cursor.
 * @head:	the head for your list.
 * @member:	the name of the list_struct within the struct.
 */
#define list_for_each_entry(pos, head, member)				\
     for (pos = list_entry((head)->next, typeof(*pos), member);		\
	  &pos->member != (head);					\
	  pos = list_entry(pos->member.next, typeof(*pos), member))

/**
 * list_for_each_entry_reverse - iterate backwards over list of given type.
 * @pos:	the type * to use as a loop cursor.
 * @head:	the head for your list.
 * @member:	the name of the list_struct within the struct.
 */
#define list_for_each_entry_reverse(pos, head, member)			\
     for (pos = list_entry((head)->prev, typeof(*pos), member);		\
	  &pos->member != (head);					\
	  pos = list_entry(pos->member.prev, typeof(*pos), member))

/**
 * list_prepare_entry - prepare a pos entry for use in list_for_each_entry_continue()
 * @pos:	the type * to use as a start point
 * @head:	the head of the list
 * @member:	the name of the list_struct within the struct.
 *
 * Prepares a pos entry for use as a start point in list_for_each_entry_continue().
 */
#define list_prepare_entry(pos, head, member)		\
     ((pos) ? : list_entry(head, typeof(*pos), member))

/**
 * list_for_each_entry_continue - continue iteration over list of given type
 * @pos:	the type * to use as a loop cursor.
 * @head:	the head for your list.
 * @member:	the name of the list_struct within the struct.
 *
 * Continue to iterate over list of given type, continuing after
 * the current position.
 */
#define list_for_each_entry_continue(pos, head, member) 		\
     for (pos = list_entry(pos->member.next, typeof(*pos), member);	\
	  &pos->member != (head);					\
	  pos = list_entry(pos->member.next, typeof(*pos), member))

/**
 * list_for_each_entry_continue_reverse - iterate backwards from the given point
 * @pos:	the type * to use as a loop cursor.
 * @head:	the head for your list.
 * @member:	the name of the list_struct within the struct.
 *
 * Start to iterate over list of given type backwards, continuing after
 * the current position.
 */
#define list_for_each_entry_continue_reverse(pos, head, member)		\
     for (pos = list_entry(pos->member.prev, typeof(*pos), member);	\
	  &pos->member != (head);					\
	  pos = list_entry(pos->member.prev, typeof(*pos), member))

/**
 * list_for_each_entry_from - iterate over list of given type from the current point
 * @pos:	the type * to use as a loop cursor.
 * @head:	the head for your list.
 * @member:	the name of the list_struct within the struct.
 *
 * Iterate over list of given type, continuing from current position.
 */
#define list_for_each_entry_from(pos, head, member) 			\
     for (; &pos->member != (head);					\
	  pos = list_entry(pos->member.next, typeof(*pos), member))

/**
 * list_for_each_entry_safe - iterate over list of given type safe against removal of list entry
 * @pos:	the type * to use as a loop cursor.
 * @n:		another type * to use as temporary storage
 * @head:	the head for your list.
 * @member:	the name of the list_struct within the struct.
 */
#define list_for_each_entry_safe(pos, n, head, member)			\
     for (pos = list_entry((head)->next, typeof(*pos), member),		\
	       n = list_entry(pos->member.next, typeof(*pos), member);	\
	  &pos->member != (head); 					\
	  pos = n, n = list_entry(n->member.next, typeof(*n), member))

/**
 * list_for_each_entry_safe_continue
 * @pos:	the type * to use as a loop cursor.
 * @n:		another type * to use as temporary storage
 * @head:	the head for your list.
 * @member:	the name of the list_struct within the struct.
 *
 * Iterate over list of given type, continuing after current point,
 * safe against removal of list entry.
 */
#define list_for_each_entry_safe_continue(pos, n, head, member)		\
     for (pos = list_entry(pos->member.next, typeof(*pos), member),	\
	       n = list_entry(pos->member.next, typeof(*pos), member);	\
	  &pos->member != (head);					\
	  pos = n, n = list_entry(n->member.next, typeof(*n), member))

/**
 * list_for_each_entry_safe_from
 * @pos:	the type * to use as a loop cursor.
 * @n:		another type * to use as temporary storage
 * @head:	the head for your list.
 * @member:	the name of the list_struct within the struct.
 *
 * Iterate over list of given type from current point, safe against
 * removal of list entry.
 */
#define list_for_each_entry_safe_from(pos, n, head, member)		\
     for (n = list_entry(pos->member.next, typeof(*pos), member);	\
	  &pos->member != (head);					\
	  pos = n, n = list_entry(n->member.next, typeof(*n), member))

/**
 * list_for_each_entry_safe_reverse
 * @pos:	the type * to use as a loop cursor.
 * @n:		another type * to use as temporary storage
 * @head:	the head for your list.
 * @member:	the name of the list_struct within the struct.
 *
 * Iterate backwards over list of given type, safe against removal
 * of list entry.
 */
#define list_for_each_entry_safe_reverse(pos, n, head, member)		\
     for (pos = list_entry((head)->prev, typeof(*pos), member),		\
	       n = list_entry(pos->member.prev, typeof(*pos), member);	\
	  &pos->member != (head); 					\
	  pos = n, n = list_entry(n->member.prev, typeof(*n), member))

/*********************************
 ** General macros 
 *********************************/

#define list_for_each_ini(pos, ini, head)	\
     for (pos = (ini)->next; pos != (head);	\
	  pos = pos->next)

#define list_for_each_safe_ini(pos, ini, n, head)		\
     for (pos = (ini)->next, n = pos->next; pos != (head);	\
	  pos = n, n = pos->next)


/*
 * Double linked lists with a single pointer list head.
 * Mostly useful for hash tables where the two pointer list head is
 * too wasteful.
 * You lose the ability to access the tail in O(1).
 */

typedef struct hlist_head hlist_head_t;
typedef struct hlist_node hlist_node_t;

struct hlist_head {
     struct hlist_node *first;
};

struct hlist_node {
     struct hlist_node *next, **pprev;
};

#define HLIST_HEAD_INIT { .first = NULL }
#define HLIST_HEAD(name) struct hlist_head name = {  .first = NULL }
#define INIT_HLIST_HEAD(ptr) ((ptr)->first = NULL)
static inline void INIT_HLIST_NODE(struct hlist_node *h)
{
     h->next = NULL;
     h->pprev = NULL;
}

static inline int hlist_unhashed(const struct hlist_node *h)
{
     return !h->pprev;
}

static inline int hlist_empty(const struct hlist_head *h)
{
     return !h->first;
}

static inline void __hlist_del(struct hlist_node *n)
{
     struct hlist_node *next = n->next;
     struct hlist_node **pprev = n->pprev;
     *pprev = next;
     if (next)
	  next->pprev = pprev;
}

static inline void hlist_del(struct hlist_node *n)
{
     __hlist_del(n);
     n->next = (void *) 0;
     n->pprev = (void *) 0;
}

static inline void hlist_del_init(struct hlist_node *n)
{
     if (!hlist_unhashed(n)) {
	  __hlist_del(n);
	  INIT_HLIST_NODE(n);
     }
}

static inline void hlist_add_head(struct hlist_node *n, struct hlist_head *h)
{
     struct hlist_node *first = h->first;
     n->next = first;
     if (first)
	  first->pprev = &n->next;
     h->first = n;
     n->pprev = &h->first;
}

/* next must be != NULL */
static inline void hlist_add_before(struct hlist_node *n,
				    struct hlist_node *next)
{
     n->pprev = next->pprev;
     n->next = next;
     next->pprev = &n->next;
     *(n->pprev) = n;
}

static inline void hlist_add_after(struct hlist_node *n,
				   struct hlist_node *next)
{
     next->next = n->next;
     n->next = next;
     next->pprev = &n->next;

     if(next->next)
	  next->next->pprev  = &next->next;
}

/*
 * Move a list from one list head to another. Fixup the pprev
 * reference of the first entry if it exists.
 */
static inline void hlist_move_list(struct hlist_head *old,
				   struct hlist_head *new)
{
     new->first = old->first;
     if (new->first)
	  new->first->pprev = &new->first;
     old->first = NULL;
}

#define hlist_entry(ptr, type, member) container_of(ptr,type,member)

#define hlist_for_each(pos, head)			\
     for (pos = (head)->first; pos && ({ ; 1; });	\
	  pos = pos->next)

#define hlist_for_each_safe(pos, n, head)			\
     for (pos = (head)->first; pos && ({ n = pos->next; 1; });	\
	  pos = n)

/**
 * hlist_for_each_entry	- iterate over list of given type
 * @tpos:	the type * to use as a loop cursor.
 * @pos:	the &struct hlist_node to use as a loop cursor.
 * @head:	the head for your list.
 * @member:	the name of the hlist_node within the struct.
 */
#define hlist_for_each_entry(tpos, pos, head, member)			\
     for (pos = (head)->first;						\
	  pos && ({ ; 1;}) &&						\
	       ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
	  pos = pos->next)

/**
 * hlist_for_each_entry_continue - iterate over a hlist continuing after current point
 * @tpos:	the type * to use as a loop cursor.
 * @pos:	the &struct hlist_node to use as a loop cursor.
 * @member:	the name of the hlist_node within the struct.
 */
#define hlist_for_each_entry_continue(tpos, pos, member)		\
     for (pos = (pos)->next;						\
	  pos && ({ ; 1;}) &&						\
	       ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
	  pos = pos->next)

/**
 * hlist_for_each_entry_from - iterate over a hlist continuing from current point
 * @tpos:	the type * to use as a loop cursor.
 * @pos:	the &struct hlist_node to use as a loop cursor.
 * @member:	the name of the hlist_node within the struct.
 */
#define hlist_for_each_entry_from(tpos, pos, member)			\
     for (; pos && ({ ; 1;}) &&						\
	       ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
	  pos = pos->next)

/**
 * hlist_for_each_entry_safe - iterate over list of given type safe against removal of list entry
 * @tpos:	the type * to use as a loop cursor.
 * @pos:	the &struct hlist_node to use as a loop cursor.
 * @n:		another &struct hlist_node to use as temporary storage
 * @head:	the head for your list.
 * @member:	the name of the hlist_node within the struct.
 */
#define hlist_for_each_entry_safe(tpos, pos, n, head, member)		\
     for (pos = (head)->first;						\
	  pos && ({ n = pos->next; 1; }) &&				\
	       ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
	  pos = n)

#endif /* ___DLLIST_H */
